Navigation data, for instance a map that shall be used by a terminal, such as for instance a hand-held navigation device or a car-mounted navigation device or the like may nowadays being stored locally at the terminal. Due to storing the navigation data locally, there may be, for instance, several limits regarding the size of the locally stored navigation data. The navigation data may contain data for different zooming levels resulting in an increased size of the navigation data.
To prevent the locally stored navigation data from becoming outdated, there may be provided incremental updates of the navigation data to the terminal, for instance by update patches. Very often, the size of the navigation data correlates to the incremental update patch size required for updating the navigation data locally stored at the terminal.
Transmission of the navigation data and/or the incremental update patches to the terminal may require relatively lots of bandwidth and/or transmission time in addition to the required memory for storing such data locally at the terminal.
It is an object of the invention to reduce the size of the navigation data locally stored at such aforementioned terminals and to reduce the size of update patches needed for preventing the locally stored navigation data from becoming outdated.